#include "stm32f10x.h"                  // Device header

int16_t Encoder_Count;

void Encoder_Init(void)
{
    
   RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB,ENABLE);
   RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);

	GPIO_InitTypeDef GPIO_InitStructure;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
    GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_0 | GPIO_Pin_1;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOB,&GPIO_InitStructure);
	
	GPIO_EXTILineConfig(GPIO_PortSourceGPIOB,GPIO_PinSource0);
	GPIO_EXTILineConfig(GPIO_PortSourceGPIOB,GPIO_PinSource1);
	
	EXTI_InitTypeDef EXTI_InitStructure;
	EXTI_InitStructure.EXTI_Line = EXTI_Line0 | EXTI_Line1;
	EXTI_InitStructure.EXTI_LineCmd = ENABLE;
	EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
	EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
	 EXTI_Init(&EXTI_InitStructure);
	
	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
	
	NVIC_InitTypeDef NVIC_InitStructure;
	NVIC_InitStructure.NVIC_IRQChannel = EXTI0_IRQn;
	NVIC_InitStructure.NVIC_IRQChannelCmd= ENABLE;
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority= 1;
	NVIC_InitStructure.NVIC_IRQChannelSubPriority= 1;
	NVIC_Init(&NVIC_InitStructure);

    NVIC_InitStructure.NVIC_IRQChannel = EXTI1_IRQn;
	NVIC_InitStructure.NVIC_IRQChannelCmd= ENABLE;
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority= 1;
	NVIC_InitStructure.NVIC_IRQChannelSubPriority= 2;
	NVIC_Init(&NVIC_InitStructure);
}

int16_t Encoder_Get(void)
{  int16_t Temp;
	Temp = Encoder_Count;
	Encoder_Count = 0;
	return Temp;
}

void EXTI0_IRQHandler(void)
{
    if(EXTI_GetITStatus(EXTI_Line0) == SET)
	{
		if(GPIO_ReadInputDataBit(GPIOB,GPIO_Pin_1)==0)
		{
		    Encoder_Count--;
		}
	    EXTI_ClearITPendingBit(EXTI_Line0);
	}
}

void EXTI1_IRQHandler(void)
{
    if(EXTI_GetITStatus(EXTI_Line1) == SET)
	{
		if(GPIO_ReadInputDataBit(GPIOB,GPIO_Pin_0)==0)
	    {
		   Encoder_Count++;
		}
		EXTI_ClearITPendingBit(EXTI_Line1);
	}
}